Revert "Clear the bitmap associated with canvases."

This reverts commit 9b9d48f289.

src/com/android/launcher2/BubbleTextView.java

@@ -200,7 +200,6 @@ public class BubbleTextView extends TextView implements VisibilityChangedBroadca
         canvas.setBitmap(b);
         drawWithPadding(canvas, padding);
         mOutlineHelper.applyExtraThickExpensiveOutlineWithBlur(b, canvas, glowColor, outlineColor);
-        canvas.setBitmap(null);
 
         return b;
     }